瞬息万变 [- - wàn biàn]vary from minute to minute; changing all the time; fast changing; instantaneous changes; many changes within a short time; undergoing a myriad of changes in the twinkling of an eye:
•¶ 外面世界是瞬息万变的。 The objective world is constantly changing.
•¶ 股票市场瞬息万变。 There were so many unpredictable fluctuations on the Stock Exchange.